Triple reaction centers Vo-Ce-CuO nanosheets with single Ce atom for the Fenton-like degradation of niflumic acid

Vo (oxygen vacancy)-Ce-CuO nanosheet catalysts were studied for degrading niflumic acid (NFA) by the heterogeneous Fenton-like process (HFLP). NFA removal percentage of optimal Vo-Ce0.05-CuO reached 92% after 60 min of Fenton-like reactions and dropped only 0.28% after five times of recycles. Synergetic effects of triple reaction centers with electron-rich Vo centers, single Ce atom centers, and electron-deficient Cu centers have been demonstrated for generating hydroxyl radicals (OH) by H2O2 decomposition. The electrons from the organic pollutants adsorbed at the electron-deficient Cu centers could be transferred to Vo and Ce via the internal bridge bond to balance the electron transfer. H2O2 could directly obtain electrons from electron-rich Vo and single Ce atom centers to produce OH with a high H2O2 utilization efficiency instead of reducing metal ions by consuming H2O2. For the first time, we demonstrate that triple reaction centers with single Ce atom could improve the conversion percentage of H2O2 to OH with 71.1%. OH, HO2/O2− and 1O2 were the primary oxidants in the HFLP, in which OH played the dominant role.